1. Field of the Invention
This invention relates to baling machines of the type used to press or compact waste material such as cans and fibrous materials, and particularly to such a baling machine in which the platen or baling head moves vertically.
2. Description of the Prior Art
Vertical or downstroke baling machines for waste material are commonly used to bale aluminum beverage cans, tin cans, other non-ferrous scrap, and secondary fiber materials. These baling machines commonly comprise a housing or cabinet having a baling chamber therein and having a vertically movable upper front door which may be opened for the insertion of material to be baled into the chamber and having a hinged lower front door which is opened to remove the bale of material from the chamber. A platen is mounted to be vertically movable within the baling chamber. The platen is in its raised upper position for the insertion of waste material into the baling machine, and is moved downwardly to compress the material into the finished bale. The platen is pushed downwardly by suitable hydraulic ram means.
Prior art baling machines of this type have commonly utilized a single hydraulic cylinder on top of the baling machine to serve as a ram means for pushing the platen downwardly. The top-mounted hydraulic cylinder, however, occupied considerable space above the machine and resulted in a baling machine having an excessive height. Because of its height, such a baling machine could not be located in many standard size rooms or work areas where the ceiling is less than the overall height of the machine. In some instances, in order to accommodate these baling machines, users have cut holes in ceilings to provide sufficient clearance for the machines.
To reduce the overall height of such baling machines, other types of machines have been developed which have a pair of side-mounted hydraulic cylinders instead of a single top-mounted cylinder. While the pair of side-mounted cylinders have resulted in a reduction in the overall height of the baling machine, the two-cylinder design required costly and complicated hydraulic valving to assure that the cylinders operated uniformly and simultaneously to pull the platen down equally on both sides. If the operation of one cylinder was not exactly equal to that of the other cylinder, the platen may jam, or serious damage could result in the baling machine. As a result, the hydraulic supply system for the two-cylinder baling machine must be designed in such a manner that it assures that both cylinders operate together. This design often requires special balancing means to assure that equal amounts of hydraulic fluid are supplied to both cylinders and other specialized and complicated components.
An example of one type of baling machine having two hydraulic cylinders is shown in U.S. Pat. No. 4,041,856, issued to Fox, in which the two cylinders are shown mounted diagonally above the platen. While this design also served to reduce the overall height of the baling machine, it required two cylinders, and thus a complicated hydraulic supply system, to assure uniform operation of both cylinders.